fmtesc.c

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/*************************************************************************
 * Copyright (c) 2011 AT&T Intellectual Property 
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors: Details at https://graphviz.org
 *************************************************************************/
 
/*
 * Glenn Fowler
 * AT&T Research
 *
 * return string with expanded escape chars
 */
 
#include <ast/ast.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <util/agxbuf.h>
#include <util/gv_ctype.h>
 
char *fmtquote(const char *as, const char *qb, const char *qe) {
    const size_t n = strlen(as);
    const unsigned char *s = (const unsigned char *) as;
    const unsigned char *e = s + n;
    bool escaped = false;
    bool spaced = false;
    bool shell = false;
 
    agxbuf b = {0};
    if (qb) {
        if (qb[0] == '$' && qb[1] == '\'' && qb[2] == 0)
            shell = true;
        agxbput(&b, qb);
    }
 
    char last = '\0';
#define PUT(ch)                                                                \
  do {                                                                         \
    last = (ch);                                                               \
    agxbputc(&b, (ch));                                                        \
  } while (0)
 
    while (s < e) {
            int c = *s++;
            if (gv_iscntrl(c) || !gv_isprint(c) || c == '\\') {
                escaped = true;
                PUT('\\');
                switch (c) {
                case CC_bel:
                    c = 'a';
                    break;
                case '\b':
                    c = 'b';
                    break;
                case '\f':
                    c = 'f';
                    break;
                case '\n':
                    c = 'n';
                    break;
                case '\r':
                    c = 'r';
                    break;
                case '\t':
                    c = 't';
                    break;
                case CC_vt:
                    c = 'v';
                    break;
                case CC_esc:
                    c = 'E';
                    break;
                case '\\':
                    break;
                default:
                    PUT((char)('0' + ((c >> 6) & 07)));
                    PUT((char)('0' + ((c >> 3) & 07)));
                    c = '0' + (c & 07);
                    break;
                }
            } else if (qe && strchr(qe, c)) {
                escaped = true;
                PUT('\\');
            } else if (!spaced &&
                       !escaped &&
                       (gv_isspace(c) ||
                        (shell &&
                         (strchr("\";~&|()<>[]*?", c) ||
                          (c == '#' && (last == '\0' || gv_isspace(last))
                          )
                         )
                        )
                       )
                )
                spaced = true;
            PUT((char)c);
    }
#undef PUT
    if (qb) {
        if (!escaped) {
            const size_t move_by = (size_t)(shell + !spaced);
            if (move_by > 0) {
                char *content = agxbdisown(&b);
                agxbput(&b, content + move_by);
                free(content);
            }
        }
        if (qe && (escaped || spaced))
            agxbput(&b, qe);
    }
    return agxbdisown(&b);
}
 
/*
 * escape the usual suspects and quote chars in qs
 */
 
char *fmtesq(const char *as, const char *qs)
{
  return fmtquote(as, NULL, qs);
}
 
/*
 * escape the usual suspects
 */
 
char *fmtesc(const char *as)
{
  return fmtquote(as, NULL, NULL);
}